The present invention provides a security device for securing a spare tire and rim, retained by a winch mechanism, to the underside of an automobile. More specifically, the device includes a securing element that engages the rim and encloses a yoke of the winch mechanism to prevent a thief from severing the yoke and gaining access to the spare tire and rim. In a use position, the yoke extends through the primary opening in the rim and a fastener extends through a hole in the securing element and a secondary opening in the rim to connect the securing element to the rim, whereby the yoke is enclosed between the rim and the securing element.